Spider Mimics

Dominion, Volume 26, Issue 290, 2 September 1933, Page 20

Spider Mimics

(By J. Drummond, F.L.S., F.Z.S., for “The Dominion.”)

RECENT references to jumping-spiders seen in Marlborough, Canterbury and Southland did not draw attention to the friendliness many species of jumping spiders show for ants. The omission may be accounted for by the neglect of New Zealand spiders by the Dominion’s naturalists, some of whom some day will find these creatures as deeply interesting here as they are elsewhere. If imitation is the sincerest form of flattery, jumping spiders flatter ants, resembling them to a surprising degree. Observers are astonished by the skill and the faithfulness with which insects mimic other insects. Spiders are not insects. The form and shape of a typical spider are very different from the form and shape of an insect’s, body. Yet here are jumping spiders with their bodies and general appearance so modified that even experienced students of ants and spiderg fail at first glance to realise that they are handling spiders, not ants. The deception does not end with outward appearance. These spiders mimic the ants’ habits, hold out their forelegs like ants’ antennae, or feelers, run hurriedly, and assume ants’ busy airs, their boldness, their mannerisms, and the personality that stamps them. There is a species of spider which, when it hunts for prey, always zig-zags from side to side in its walk, and holds up a pair of legs in front of Its head as if they were antennae. No spiders possess these useful appendages, but, although greatly diversified in length and structure they are part of every insectfs equipment. Spiders that mimic ants at the meal table do not stand still, as most spiders do, but twitch their bodies continually and pull their prey this way and, that way, imitating an ant's restless movements during the meal. In the tropics there are tree-ants notorious for their fierceness and their pugnacity. Wherever they occur in large numbers, a species of jumping spiders is found running among them,

wearing a similar black and white costume and moving with the same hurried actions. The spiders seem to be on tlie friendliest footing with their fierce associates, which give people a painful and lasting bite. Close to every large colony of an Indian ant there are mimicking spiders. A particular species of ant and a particular species of spider occupy the same grassy slopes at Portland, England. The spiders resemble the ants so closely that a spider can be distinguished from an ant only by careful examination. Both, on the approach of danger, seek the shelter of tangled grass or the roots of other small plants. . A species of spider in the tropics that lives with a species of small reel ants mimics it in almost every way. The spider is orange-red picked out with a pair of black spots at the end of its body, which s cylindrical and elongated, rounded in front and behind, but constricted in the middle, spider’s body resembles the ant’s body, their waists coirespond, and the end of the spider’s body, with conspicuous black spots, resembles the ant's chest, head and two eyes. The peculiar feature of this form of anomalous mimicry is that the spider’s hind end corresponds to the ant’s front. The explanation offered is that this species of spider has a habit of moving sideways and backwards with almost greater facility and frequency than it moves forward. Its hind end often is where its head should be. . While mimicry of ants is perhaps spiders’ boldest device in this respect, they have a big box of tricks. Some of them mimic snails, ignored by wasps and by ichneumon flies. There is a spider which, by clinging to the under-side of a leaf with legs drawn up, resembles, in shape and colour, a small snail plentiful in the same place. The spider sticks like a snail when its leaf is shaken roughly. Several species of spiders mimic the nauseous ladybirds. Many spiders resemble their own cocoon. Others resemble the berries of a plant.